This paper presents a riew motion vector coding scheme based on bottom-up merging procedure. For low motion video sequences, most of the storage space of the motionvector data spending on the low motion objects or st...
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ISBN:
(纸本)9781424444717
This paper presents a riew motion vector coding scheme based on bottom-up merging procedure. For low motion video sequences, most of the storage space of the motionvector data spending on the low motion objects or stills back ground. The proposed scheme merges the neighboring macroblocks with similar motionvectors in to bigger rectangular blocks, and those merged blocks may represent as all ora part of the objects and the background. For the merged blocks, each block will need only one motionvector to reconstruct it. Experimental results show that the proposed scheme can reduce about 50% motion vector coding bits as compared to the conventional way of storing motionvectors for each macroblock.
We propose a new method for improving motion vector coding. The coding efficiency of the H.264/AVC standard is significantly degraded for video sequences that include irregular motions. The degradation is caused by th...
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ISBN:
(纸本)9781424445936
We propose a new method for improving motion vector coding. The coding efficiency of the H.264/AVC standard is significantly degraded for video sequences that include irregular motions. The degradation is caused by the fact that the correlations among the motionvectors on adjacent blocks get to be small when motions are irregular. Our method solves this problem by two schemes. First, the predictive motionvector (PMV) is adaptively coded with additional bits based on the distribution pattern of reference vectors. Second, an appropriate code table for the motionvector difference (MVD) is adaptively selected out of a couple of tables defined in advance. These schemes enable the appropriate methodologies for the motion vector coding to be adaptively selected according to the motionvector diversity. Experimental results show the effectiveness and potentiality of our approach for high coding efficiency.
We present an adaptive quarter-pel (Qpel) motion estimation (ME) method for H.264/AVC. Instead of applying Qpel ME to all macroblocks (MBs), the proposed method selectively performs Qpel ME in an MB level. In order to...
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We present an adaptive quarter-pel (Qpel) motion estimation (ME) method for H.264/AVC. Instead of applying Qpel ME to all macroblocks (MBs), the proposed method selectively performs Qpel ME in an MB level. In order to reduce the bit rate, we also propose a motionvector (MV) encoding technique that adaptively selects a different variable length coding (VLC) table according to the accuracy of the MV. Experimental results show that the proposed method can achieve about 3% average bit rate reduction. (C) 2009 Society of Photo-Optical Instrumentation Engineers. [DOI: 10.1117/1.3257262]
The problem of inter-description motionvector redundancy control in scalable multiple description video coding is addressed in this paper. In the motion compensated temporal filtering (MCTF) followed by the multiple ...
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ISBN:
(纸本)9781622762675
The problem of inter-description motionvector redundancy control in scalable multiple description video coding is addressed in this paper. In the motion compensated temporal filtering (MCTF) followed by the multiple description scalar quantization (MDSQ) of texture data approach, the same set of motionvectors are repeated in both descriptions. While this repetition of motionvector data adds extra overhead, they do not contribute to self correcting of errors as in MDSQed texture data during joint decoding. The paper proposes interleaving of motionvector fields between the descriptions and MDSQ of motionvectors to obtain two correlating motionvector fields rather than repeating them. The results show superior performance of MDSQ of motionvectors compared to other approaches.
We propose a derivation scheme of a motionvector for interlace format. The adjustment of the vertical component of a chroma MV for 4: 2: 0 format and the adjustment of the vertical component of a luma prediction MV a...
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ISBN:
(纸本)9781457720482
We propose a derivation scheme of a motionvector for interlace format. The adjustment of the vertical component of a chroma MV for 4: 2: 0 format and the adjustment of the vertical component of a luma prediction MV are introduced in order to remove inconsistency between the current derivation process of motionvector predictor and the nature of interlace format in HM4.0. The proposed scheme achieves up to 1.0dB PSNR improvements in chroma components and up to 3.4% bit-rate reduction.
The demand of real-time yet high quality video encoding for portable multimedia devices is increasingly strong. The state of the art H.264/AVC standard provides much higher coding efficiency than its predecessors. How...
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The demand of real-time yet high quality video encoding for portable multimedia devices is increasingly strong. The state of the art H.264/AVC standard provides much higher coding efficiency than its predecessors. However, its high computational complexity of encoding is not suitable for battery-powered mobile devices. In this paper, we introduce a low complexity video encoding scheme based on new pooled macroblock modes mainly targeted for battery-operated portable devices. Since the motion prediction and intra prediction take most of the computation and thus battery consumption, restriction of prediction block sizes is essential in implementing a low complexity encoder. However, if this is not done carefully, it may result in unacceptable degradation of coding efficiency. The problem is overcome by developing new macroblock coding modes which are computationally trivial but effective in coding efficiency. Experimental results with several well-known video test sequences verify a far better performance of the proposed method against the standard H.264/AVC encoder operated in low-complexity configuration. Also we evaluate how less power consumption the proposed low complexity encoder actually consumes compared to that of the H.264/AVC baseline profile.
The state-of-the-art median prediction scheme is widely used for predicting motionvectors (MVs) in recent video standards. By exploiting the spatial correlations among MVs, median prediction scheme predicts MV for cu...
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The state-of-the-art median prediction scheme is widely used for predicting motionvectors (MVs) in recent video standards. By exploiting the spatial correlations among MVs, median prediction scheme predicts MV for current block from three neighboring blocks. When MV is obtained from motion estimation, MV difference (MVD) is calculated and then transmitted. This process for predicting MV and calculating MVD is known as MV coding process. For MV coding, the performance depends on how efficient both the spatial and the temporal correlations among MVs are being exploited. Median prediction scheme applies a sophisticated way including some special rules to exploit the spatial correlations, however the temporal correlations among successive MVs are not exploited. In this paper, a new algorithm named MV pattern matching (MV-PM) exploiting both the spatial and temporal correlations is proposed. Various kinds of experimental results show that the proposed MV-PM algorithm outperforms the median prediction and the other related prediction schemes. (C) 2011 Elsevier Inc. All rights reserved.
Since many video coding methods use prediction between motion-compensated frames, the motionvector must be transmitted. A large amount of code is generated for DCT coefficients for the motionvector. Therefore, predi...
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Since many video coding methods use prediction between motion-compensated frames, the motionvector must be transmitted. A large amount of code is generated for DCT coefficients for the motionvector. Therefore, prediction is performed from the motionvectors of neighboring blocks and variable-length coding of the horizontal and vertical components of the prediction error vector is performed to reduce the amount of generated code. However, since this method handles the horizontal and vertical components as independent components, appropriate code assignment for coding the prediction error vector may not he possible. In this paper, the authors propose a method of coding by using norm and angle components to represent the prediction error vector and compare its coding efficiency with the conventional method to show its effectiveness. (C) 2006 Wiley Periodicals, Inc.
The H.264/MPEG4-AVC video coding standard has achieved a higher coding efficiency compared to its predecessors. The significant bitrate reduction is mainly obtained by efficient motion compensation tools, as variable ...
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The H.264/MPEG4-AVC video coding standard has achieved a higher coding efficiency compared to its predecessors. The significant bitrate reduction is mainly obtained by efficient motion compensation tools, as variable block sizes, multiple reference frames, 1/4-pel motion accuracy and powerful prediction modes (e.g., SKIP and DIRECT). These tools have contributed to an increased proportion of the motion information in the total bitstream. To achieve the performance required by the future ITU-T challenge, namely to provide a codec with 50% bitrate reduction compared to the current H.264, the reduction of this motion information cost is essential. This paper proposes a competing framework for better motion vector coding and SKIP mode. The predictors for the SKIP mode and the motionvector predictors are optimally selected by a rate-distortion criterion. These methods take advantage from the use of the spatial and the temporal redundancies in the motionvector fields, where the simple spatial median usually fails. An adaptation of the temporal predictors according to the temporal distances between motionvector fields is also described for multiple reference frames and B-slices options. These two combined schemes lead to a systematic bitrate saving on Baseline and High profile, compared to an H.264/MPEG4-AVC standard codec, which reaches up to 45%.
In the scalable video coder MC-EZBC,(1) the scalability for motionvectors was not provided, and this greatly impacts its performance when scaling down to very low bit rates and resolutions. Here we enhance MC-EZBC wi...
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ISBN:
(纸本)0819456586
In the scalable video coder MC-EZBC,(1) the scalability for motionvectors was not provided, and this greatly impacts its performance when scaling down to very low bit rates and resolutions. Here we enhance MC-EZBC with scalable motion vector coding using the Context based Adaptive Binary Arithmetic Coder (CABAC).(2) Both a layered structure for motion vector coding and an alphabet general partition (AGP)(3) of the motionvector symbols are employed for SNR and resolution scalability of the motionvector bitstream. With these two new features and the careful arrangement of the motionvector bitstream output from the existing MC-EZBC, we obtain temporal, SNR, and resolution scalability for motionvectors. This significantly improves both visual and objective performance at low bit rates and resolutions with only a slight PSNR loss (about 0.05 dB), but no detectable visual loss, at high bit rates.
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